UNUSUAL TEMPERATURE DEPENDENCE OF COERCIVITY IN Ε-FE2O3 PHASE

1 Nikolić Violeta N.
Co-authors:
1 Tadić Marin 1 Mraković Ana 1 Spasojević Vojislav
Institution:
1 University of Belgrade - Vinča Institute of Nuclear Sciences, Condensed Matter Physics Laboratory, P.O. Box 522, 11001 Belgrade, Republic of Serbia, violeticanik@gmail.com
Conference:
9th International Conference on Nanomaterials - Research & Application, Hotel Voronez I, Brno, Czech Republic, EU, October 18th - 20th 2017
Proceedings:
Proceedings 9th International Conference on Nanomaterials - Research & Application
Pages:
27-32
ISBN:
978-80-87294-81-9
ISSN:
2694-930X
Published:
8th March 2018
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
132 views / 56 downloads
Abstract

Nano iron oxides have been intensively investigated due to their various potential biomedical applications. ε-Fe2O3phase exerted internal coercivity value up to ~20 kOe, high Curie temperature (Tc= 510 K), and magnetoelectric character. Accordingly, epsilon phase is recognized as a suitable material for medical spintronic biosensors production, that present important part for the lab-on-a-chip systems. Noteworthy, ε-Fe2O3 phase exerts peculiar magnetic behavior. To get better insight into the magnetism of this material, ε-Fe2O3/SiO2 sample was prepared by the combination of the sol-gel synthesis and microemulsion method (Tann=1050 °C, tann= 4h). Afterwards, the sample was exposed to post-annealing treatment at 100 °C and 200 °C. Synthesized material was preliminary examined by XRD and SQUID techniques. Coercivity changes, induced by the post-annealing temperature oscillations, were monitored by hysteretic measurements. Sample annealed at 1050 °C for 4h, showed coercivity ~20 kOe. The same sample performed to the post-annealing treatment at 100 °C, exerted significantly decreased coercivity (~1600 Oe). Further rise of the post-annealing temperature (200 °C) resulted in the increased coercivity ~15 kOe. Obtained study showed that there is insufficientknowledge concerning theε-Fe2O3coercivity changes of thepolymorph. The more detailed investigation will be conducted, in order to advance the control of the epsilon phase magnetic properties.

Keywords: ε-Fe2O3 phase, coercivity, phase transformations

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